I did the Speed C25Kplus on Wednesday. But I was very confused. To start with the walking speed was considerably slower than I normally do. Then the slow running speed was also slower than my normal. When we got to the fast rate I felt more comfortable (but don't know how long I could have kept it up). At the end I felt like I had had an easy session.
This is supposed to be speeding me up not slowing me down. And I am not a fast runner. I am a very slow jogger - barely do 2 miles in 30 minutes, so shuffle along with short fast steps.
Maybe this is designed for people with long legs .Mine are very short. ;p